Learn: Energy Stores and Transfers

Welcome!I've reviewed your progress and noticed that you're working on improving your understanding of Energy Stores and Transfers. This lesson will help you learn about energy, how it is stored, and how it moves from one place to another.

What are Energy Stores?Energy stores describe where energy is stored in a system. Examples include kinetic energy (energy of moving objects), thermal energy (energy due to heat), and chemical energy (stored in food or fuel). These stores help us understand how energy moves and changes in different situations.

What are Energy Transfers?Energy transfers occur when energy moves between stores. This can happen through processes like heating, work done (force moving an object), or radiation (light or sound waves). Energy cannot be created or destroyed; it is only transferred between stores, which follows the law of conservation of energy.

How is Energy Transferred?Energy can be transferred in several ways. For example, when a ball is dropped, gravitational potential energy is transferred into kinetic energy. Similarly, when you boil water, heat energy is transferred from the kettle to the water. Energy transfer explains how energy moves from one store to another.

The Law of Conservation of EnergyThe law of conservation of energy states that energy cannot be created or destroyed; it can only be transferred or transformed. This means that the total energy in a closed system remains constant, even if it changes forms.

Work Done and Energy TransfersWhen a force moves an object, energy is transferred to or from its kinetic energy store. This is called work done. For example, when you lift a box, energy is transferred to its gravitational potential energy store. Work is calculated using the formula: Work done = force × distance.

Energy EfficiencyWhen energy is transferred, some of it is often wasted as thermal energy. The efficiency of a process tells us how much of the input energy is usefully transferred. Efficiency is calculated using the formula: Efficiency = (useful energy output ÷ total energy input) × 100.

Energy Transfer DiagramsWe can use energy transfer diagrams to show how energy moves between stores. For example, when a car engine burns fuel, chemical energy is transferred to kinetic energy (movement) and thermal energy (heat).

Review Time!Great work! You've learned about energy stores, energy transfers, and efficiency. Now let's test your understanding with a few questions.